A white powdery substance found in an envelope Monday addressed to Donald Trump Jr. triggered a security scare, as well as a brief hospital visit for his wife, but tests determined it later to be nothing more than cornstarch, law enforcement officials said.

Trump’s wife, Vanessa, opened the envelope, addressed to her husband, when it arrived at 10 a.m. at the East 54th Street home of her mother in the Sutton Place neighborhood, an NYPD spokesman said.

Police hazmat units, as well as the Secret Service responded and took possession of the envelope and its contents for testing. Vanessa Trump, who showed no adverse effects from the exposure, was taken to New York Presbyterian Hospital for observation, and released, officials said.

NYPD hazmat units tested the material for biological, chemical and radiological content, but determined it was cornstarch, a police spokesman said. Vanessa Trump’s mother, Bonnie Haydon, and a third person in the apartment were also examined at the hospital and released, said officials.

Trump, 40, and his wife, the former Vanessa Haydon, were married in 2005 and have five children. A spokesman for the Trump Organization, for which Trump Jr. is a key executive, didn’t return a request for comment. Michael Cohen, the personal attorney for President Donald Trump and Bonnie Haydon, also didn’t return calls for comment.